Vending machines with field-programmable locks

ABSTRACT

A vending machine uses a field-programmable electronic lock that learns a key code from a corresponding electronic key. The electronic lock has a learning process activation device that is accessible only when the door of the vending machine is in the open position. Using the learning process activation device, a service person activates the electronic lock to perform a key code learning operation, in which the electronic lock receives a key code transmitted from an electronic key and stores the key code in a non-volatile memory for future access control of the vending machine. Data encryption is employed in the communications between the key and the lock to ensure the security of the communications. Customized access limitations and a list of lock IDs are programmed into the electronic key to restrict when and how it can be used to access the vending machines. Access history data of the vending machines are collected for audit purposes by uploading the data from the vending machines to an electronic key. A communication device installed in the vending machine for communicating with a home base computer allows the operation of the electronic lock to be remotely controlled for access control and auditing purposes.

RELATED APPLICATION

[0001] This application claims the priority of U.S. ProvisionalApplication No. 60/344,221 filed Dec. 27, 2001.

TECHNICAL FIELD

[0002] This invention relates generally to vending machines, and moreparticularly to vending machines equipped with electronic locks.

BACKGROUND OF THE INVENTION

[0003] Vending machines are widely used in various locations asautomated means for selling items such as soft drinks, snacks, etc.Traditional vending machines are equipped with mechanical locks, whichcan be unlocked with a corresponding mechanical key to open the door ofthe machine to allow reloading of goods and collection of money.

[0004] One significant problem with conventional vending machines is thedifficulties in managing the distribution and usage of the keys toensure the security of the locks on the vending machines. The process ofcollecting money from the vending machines scattered at different placesis a very manpower-intensive operation that requires many employees togo into the field with numerous mechanical keys for operating the lockson the vending machines. It requires a considerable amount of attentionand efforts to manage and track the distribution of the keys to thefield workers to keep the keys secure.

[0005] Moreover, the mechanical keys and lock cores of vending machinesare a point of attack for vandals. The keys can be lost or copiedeasily, and the stolen or copied keys may then be used by anunauthorized person to access the machines, and it is difficult todiscover such misuses and security breaches. Also, a skilled vandal caneasily pick or drill-out the lock core tumblers and measure the key cutsof the lock core tumblers to re-produce a like key and compromise thesecurity. In the event a security breach is identified, the mechanicallock cores of the affected vending machines typically have to bemanually replaced, which is a time-consuming and very costly process.Furthermore, mechanical keys and locks are devices that cannot bepartially limited in operation they operate indefinitely if in use.Also, they do not have the ability to record access operation attemptsof their operation.

SUMMARY OF THE INVENTION

[0006] In view of the foregoing, the present invention provides avending machine with a field-programmable electronic lock. Theelectronic lock can learn a key code from a corresponding electronickey. Alternatively, the electronic lock can learn that it should beaccessed by an electronic switch controlled by a mechanical lock thatcan be opened with an associated mechanical key. The electronic lock hasa learning process activation device that is accessible only when thedoor of the vending machine is in the open position. Using the learningprocess activation device, a service person sets the electronic lock ina learning mode, in which the electronic lock receives a key codetransmitted from an electronic key, and stores the key code in anon-volatile memory for future access control of the vending machine. Inthe case where the lock access is to be controlled by the switch-lockcombination, during the learning process the electronic lock controllerreceives an electronic closure signal from the switch. The lock thuslearns that it is to open the door of the vending machine in response ofthe switch signal in lieu of reception of key codes from electronickeys.

[0007] The key-learning process in accordance with the invention allowselectronic locks in vending machines to be easily and inexpensivelyprogrammed in the field. Thus, the electronic locks do not have to bemanufactured with pre-defined permanent key codes and are not tied toany specific electronic keys for field use. There is no need to replaceany physical part of the electronic lock in this key-learning process tolearn a new key code and/or replacing an old key code. In contrast,mechanical locks conventionally used on vending machines have lock coresthat have to be manufactured for specific keys, and once manufacturedthe lock cores cannot be changed. If the mechanical key is lost, theentire lock cores have to be replaced. More than one electronic key canpossess a given keycode. The electronic lock on a vending machine canallow more than one keycode to be learned into the lock and used toaccess the lock.

[0008] The use of the field-programmable electronic locks for vendingmachines provides an effective way to reduce theft and fraud in terms ofunauthorized access to the machines. The electronic keys provide agreater level of key security compared to mechanical keys, as theycannot be copied as easily as conventional mechanical keys. The use ofnon-contact wireless data communication between the key and the lockprevents breeches of security associated with vandals measuring keycuts, copying keys and picking locks. The use of data encryption in thewireless communications between the key and the lock prevents the keycode from being copied by electronic monitoring and eavesdropping. Thedata transmission between the key and lock may be implemented in theinfrared range to provide close-proximity highly directionalcommunication of secure codes to further prevent eavesdropping of thesecurity codes and to prevent accidental unlocking of locks.

[0009] The use of programmable electronic locks on vending machines andthe associated electronic keys also provides advantages in terms ofsignificant reduction in the costs associated with managing thedistribution of the keys for unlocking the machines and the monitoringof the usage of the keys. Key IDs in addition to the key codes used inaccessing the lock may be used to distinguish keys having the same keycodes. Customized access limitations may be programmed by a supervisorinto the electronic keys to restrict when and how they can be used toaccess the vending machines. Each key may also be programmed with aspecific list of lock IDs identifying the electronic locks on vendingmachines that the key is allowed to unlock.

[0010] In accordance with one aspect of the invention, a history ofaccess attempts may be stored in each of the electronic key and theelectronic lock for audit purposes. The key may store the access historyeach time it is used to access an electronic lock on a vending machine.Likewise, each electronic lock on a vending machine may store audit dataregarding the access attempts directed to it. The audit data may betransferred from the electronic lock to the electronic key during anunlocking operation, and the audit data of different vending machinescollected by an electronic key can be later downloaded to a computer foranalysis.

[0011] In accordance with another aspect of the invention, theelectronic lock may accept more than one type of keys and correspondingkey codes. The different key types may be associated with differentlevels of security of the unlocking operations and the type of datatransmitted between the key and lock during the unlocking operations.

[0012] In accordance with another aspect of the invention, theelectronic lock in a vending machine can work in conjunction with anelectronic communication device in the vending machine that is inwireless communication with a home base to accomplish many of the sameaccess control, auditing, and additionally some inventory and moneysettlement processes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic view of a vending machine and an electronickey for opening an electronic lock inside the vending machine;

[0014]FIG. 2 is a perspective view of an electronic lock assemblymounted on a door of a vending machine;

[0015]FIG. 3 is a block diagram showing electronic circuit components ofan electronic lock used in a vending machine;

[0016]FIG. 4 is a block diagram showing electronic circuit components ofan electronic key;

[0017]FIGS. 5A and 5B are schematic diagrams showing key codes stored inthe memories of an electronic key and an electronic lock, respectively;

[0018]FIG. 6 is a schematic diagram showing the transmission of databetween an electronic lock on a vending machine and an electronic keyduring a simplified unlocking process;

[0019]FIG. 7 is a schematic diagram showing communications between anelectronic lock on a vending machine and an electronic key during anunlocking process that has higher security than the process in FIG. 6;

[0020]FIG. 8 is a schematic diagram showing communications between anelectronic lock on a vending machine and an electronic key during anunlocking process similar to that FIG. 7 but with a step of checking thelock ID for access control;

[0021]FIG. 9 is a schematic diagram showing a computer used to programoperational limitations into an electronic key;

[0022]FIG. 10 is a schematic diagram showing the downloading of auditdata from vending machines to an electronic key; and

[0023]FIG. 11 is a schematic diagram showing an example of audit datauploaded from a vending machine to an electronic key.

[0024]FIG. 12 is a flowchart showing the key code learning process of anembodiment of the electronic lock;

[0025]FIG. 13 is a flowchart showing an operation by an embodiment ofthe electronic key to back up the time and date for restoring the clockof the key in case of a faulty or removed battery;

[0026]FIG. 14 is a flow chart showing an operation by the electronic keyto record the number of power-up of the key to prevent tampering bybattery removal;

[0027]FIG. 15 is a schematic block diagram showing an embodiment of avending machine that has a communication device that is interfaced tothe electronic lock and in wireless communications with a home base foraccess control and auditing purposes; and

[0028]FIG. 16 is a schematic diagram showing vending machines accessibleby an electronic key that has a narrow wireless signal transmissionpattern to avoid accidental opening of the vending machines.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

[0029] Referring now to the drawings, the present invention is directedto an electronic lock system for use in vending machines that providessignificantly improved security and ease of management over conventionalvending machines equipped with mechanical locks. The term “vendingmachine” as used herein means a device that performs a moneytransaction, which may involve the insertion of cash or commercialpaper, or the swiping of a credit and/or debit card, and may (but notrequired to) dispense an item or items or provide functions in responseto the money transaction. In this regard, this term is meant to coverbroadly machines commonly used for vending drinks and snacks, ATMstations, change machines, toll machines, coin-operated laundrymachines, video arcades, etc. FIG. 1 shows, as an example, a vendingmachine 20 with an embodiment of an electronic lock of the inventionmounted therein. The vending machine 20 has a front panel 22 or doorthat can be opened when the electronic lock is unlocked with a properlyprogrammed electronic key 26. It will be appreciated that the vendingmachine and the electronic key are not shown to scale in FIG. 1, and theview of the electronic key is significantly enlarged with respect to thevending machine to show its features.

[0030] The key 26 and the lock preferably communicate with each otherwirelessly, which may be via an infrared or radio frequency (RF)channel. In a preferred embodiment, the wireless communications betweenthe key and the lock is via infrared transmissions. The infrared mediumis preferred because it is directional and short range, and the infraredcircuitry in the lock is not sensitive to the metal cabinet enclosure ofthe vending machine. Thus the vending machine will less likely be openedaccidentally if the key is accidentally operated of if the key isoperated to unlock another vending machine nearby. In addition, theinfrared light can travel through the selection buttons on the vendingmachine. This allows the infrared transceiver of the electronic lock tobe positioned behind a selection button 30 of the vending machine, asillustrated in FIG. 1. To that end, the vending machine 20 has aninfrared transceiver disposed to receive infrared transmission throughits front panel 22, and the electronic key 26 has an infraredtransceiver at one end 32. As shown in FIG. 1, in one implementation,the electronic key 26 has a very simple profile, having only a “START”button 36 that can be activated by a user for lock opening and key codelearning operations. In a preferred embodiment, the “START” button 36need not be continuously pressed in order for the key to transmit theencrypted code to the lock. Instead, the user only has to onlymomentarily press the button 36, and the key will automatically stoptransmitting after a few seconds, thus the key will not transmitindefinitely and deplete the battery if the button is stuck down. Theelectronic key 26 also has a light-emitting diode (LED) 38 exposedthrough a hole in the housing of the key for indication the operationstatus of the key.

[0031] In accordance with an aspect of the invention, the electroniclock assembly is mounted inside the vending machine 20 to preventunauthorized access and tampering. It can be physically accessed onlywhen it is properly unlocked and the door 22 or front panel of thevending machine is opened. In one embodiment, as shown in FIG. 2, theelectronic lock assembly 48 is mounted on the inside of the door 22, andopening the door of the vending machine exposes the lock assemblyhousing 40. The electronic lock 48 includes a lock shaft 42 that engagesinto a corresponding receptacle in the body of the vending machine toprevent the door from being opened when it is in a locked position. Theelectronic circuit of the lock resides in the housing 40 of the lockassembly. The housing 40 has two holes. Behind one hole 44 is a “LEARN”switch connected to the electronic lock circuit. This switch can beaccessed and pressed down with a thin object, such as a screwdriver or acar key. Behind the other hole 46 is a light-emitting diode (LED), whichservers as a means for providing an indication of the operational stateof the electronic lock during a key code learning operation or a lockopening operation, as will be described in greater detail below.

[0032] Turning now to FIG. 3, in one embodiment, the circuit of theelectronic lock 48 comprises a microcomputer 50, a non-volatile memory52, a half-duplex IRDA infrared communication interface 54 forcommunicating with an electronic key, a power supply voltage regulator56, a lock motor or solenoid control circuit 58, position feedbackswitches 60, a learn switch 62 as mentioned above, and the LED 64 forstate indication. The non-volatile memory is for storing key codes 68,encryption codes 70, and audit data 72, as will be described in greaterdetail below.

[0033] In an alternative embodiment, the vending machine with theelectronic lock is to be accessed using a mechanical key rather than anelectronic key. To that end, the electronic lock includes an interfaceto a combination (the “switch-lock” combination) of an electrical switch74 and a mechanical lock 76 that has a cam for moving the switch into aclosed or open position. The electrical switch 74 is normally in an openstate and is closed when the mechanical lock 76 is opened using anassociated mechanical key 78. The open/close state of the switch 76 isdetected by the microcomputer 50 and is used to determine whether themechanical lock 76 is opened or closed. T The microcomputer 50 isprogrammed to unlock the door 22 of the vending machine 20 in responseto the closing of the switch contact caused by unlocking of themechanical lock 76 using the mechanical key 78. Thus, the unlockingprocess does not involve the passing of a key code between theelectronic lock and an electronic key. Accordingly, as described ingreater detail below, during a learning process, the electronic locklearns that it is to be accessed using a mechanical key instead of anelectronic key with a key code.

[0034] As shown in FIG. 4, in one embodiment, the electronic key 26includes a microcomputer 80, a non-volatile memory 82, a half-duplexIRDA infrared communication interface 84 for communicating with theelectronic lock of a vending machine or with a computer for programmingthe key, a power source (e.g., a battery) 86, a real-time clockintegrated circuit (IC) 94 for generating data indicating the date andtime, and the “START” switch 36 and the LED light 38 as mentioned above.The non-volatile memory 82 is for storing a key code 88, encryptioncodes 90, and audit data 92 generated by the key and/or downloaded fromvending machines operated using the key, as will be described below.

[0035] The key codes in the keys and the locks of the vending machinesare used to define the security and access control strategy of theelectronic lock system. Each electronic key 26 has a key code 88 storedtherein, and the same key code is stored in the memory 52 of theelectronic lock in each vending machine to be operated with theelectronic key. During each access attempt, the key code in theelectronic key is transferred from the key to the electronic lock usinga secured communication method. The electronic lock can be unlocked ifthe key code it receives from the electronic key matches the key codestored in the memory of the lock.

[0036] In one implementation as shown in FIG. 5A, a key code 68 storedin an electronic key includes seven (7) digits. The first digit of thekey code is used to indicate the type of the key. As the value of thekey-type digit may go from 0 to 9, there may be up to 10 total keytypes. As will be described below, in one embodiment of the electroniclock system, there are three different key-types: low-security key,standard key, and auto-tracking key, which correspond to differentlevels of security in lock-opening operation and audit data collection.The next 6 digits in the key code are the access code (000,000 to999,999). In addition to the 7 digits representing the key type andaccess code, a key code stored in the electronic key additionallyincludes two lower digits, which may be used as the identification (ID)code of that key. In this example, the key ID may vary from 0 to 99.Thus, there may be up to 100 keys that have the same key type and accesscode but different key ID numbers.

[0037] Similarly, as shown in FIG. 5B, a key code 68 stored in theelectronic lock has seven (7) digits. The first digit indicates the keytype, and the remaining 6 digits are the access code. As mentionedabove, there may be up to 10 different key types, and the electroniclock may be programmed to accept a number of key codes of different keytypes.

[0038] In accordance with a feature of the invention, the electroniclock 48 of the vending machine 20 is field-programmable. In other words,the key code or key codes of the electronic lock 48 can be programmed(or “learned”) into the non-volatile memory 52 of the lock after thevending machine has been installed in a given location. In a preferredembodiment, the electronic keys to be used to operate the vendingmachines are programmed with a permanent key code at the factory andordered by the users of the electronic locks. In the example givenabove, the users may order up to 100 keys with the same access code. Incontrast, the electronic locks to be used in the vending machines arenot programmed with any customer-specific key code. Instead, theelectronic locks are programmed with a universal code at the factory.The “universal code” is the code put in the lock by the manufacturer ofthe lock or the vending machine, and is used by the customers to unpackand open the machines after they receive the machines. Thereafter, theelectronic locks are installed in the vending machines, which are thenshipped to and set up at their respective operating places. Inaccordance with the invention, the access control strategy isestablished by “learning” or transferring the access code of theelectronic key to be used to operate the machine into the electroniclock via a secured transfer process.

[0039] Referring back to FIGS. 1-3 and 12, in one embodiment, to makethe electronic lock 48 learn the access code from an associatedelectronic key 22 or that it is to be controlled by a switch-lock, theservice person has to gain access to the LEARN switch 62 of the lock. Inaddition, it is preferred that the lock microcomputer senses, using theposition switches 60, that the lock is in the unlocked position to allowentering into the “learn” mode (step 260 in FIG. 12). To that end, ifthe door 22 of the vending machine is originally closed and the lockcontains the universal key code programmed at the factory, the serviceperson uses a key containing the universal key code to unlock thevending machine and open the door to gain access to the LEARN button ofthe lock. As mentioned above, the LEARN switch 62 should be at a securedlocation such that it can be accessed only when the lock is properlyunlocked (as opposed to a forced entry) and when the door is open. Anassumption in the access control strategy is that an authorized personis servicing and/or reprogramming the lock if the door is properlyunlocked and opened. If the microcomputer 50 detects (step 262) that theLEARN switch 62 is pressed (e.g., held for longer than three seconds),it waits (step 266) for the switch to be held in that position for apre-selected time period (e.g., 3 seconds) and then enters a LEARNprocess (step 268). In response to the pressing of the learn button, theLED 64 is turn on (step 270). In alternative embodiments, the LEARNswitch 62 can be substituted by another activation means that provides agreater level of security, such as a keypad for entering a serviceauthorization code or an electromechanical switch lock that requires amechanical or another electronic key.

[0040] Once the lock 48 is put in the LEARN mode, the service personoperates the electronic key 22 containing the desired key code bypressing the button 36 on the key. This causes the key 22 to transmitthe key code stored in its memory to the electronic lock. If theelectronic key and the lock employ encryption techniques in theircommunications, the electronic key 22 first encrypts the key code 88with the encryption codes 90 in its non-volatile memory and thentransmits the encrypted code.

[0041] The service person is given a pre-selected timeout period (e.g.,15 seconds) to press the key to transmit the key code. To that end, thelock 48 determines whether it has received the transmitted key code(step 272). If it determines (step 274) that a key code transmission isnot received within the timeout period, the learning process isterminated. If a key code has been transmitted within the timeoutperiod, the electronic lock 48 receives the transmitted key code via itsreceiver port 30. If the transmitted code is encrypted, the electroniclock decrypts the received data with the encryption codes 72 in itsmemory 52. In a preferred embodiment, the encryption codes in theelectronic key and the electronic lock are inserted during manufacturingat the factory, and different encryption codes may be used for differentvending machine owners (e.g., different soft drink bottlers) so the keysgiven to one owner may not be learned into and used to access thevending machines of another owner.

[0042] If the encryption codes of the key and the lock do not match, theelectronic lock will not be able to successfully decrypt the receivedkey code. In that case, the process will end and the lock will not learnthe new key code. If, however, the decryption was successful, the lockstores the key code at a proper location in its non-volatile memory 52according to its key type (step 276). After verifying that the key codeis stored correctly in the proper key type location, the lock 48provides a signal to the service person by flashing the LED 64 toindicate that the LEARN process is successfully completed (step 278).From this point forward, the electronic lock will use the newly learnedkey code for access control. In other words, it will compare this keycode with the key code transmitted from an electronic key to determinewhether the door should be unlocked. If there was a key code of the samekey type previously stored in the memory 52 prior to the LEARNoperation, that old key code will be erased and can no longer be used toaccess the vending machine.

[0043] As mentioned above, in an alternative embodiment, the vendingmachine equipped with the electronic lock may be accessed with amechanical key rather than an electronic key. The electronic lock learnsthat it is to be controlled by the combination of the electrical switch74 and the mechanical lock in a learning process similar to the one forlearning a key code as described above. Specifically, to enable the lockaccess via the switch-lock, the service person puts the electronic lockinto the learn mode by pressing the LEARN switch 62 as described above.Once the electronic lock 48 is in the learn mode, the service personuses the mechanical key 76 to unlock the mechanical lock 76. When themechanical lock 76 is moved to its unlocked position, its cam closes thecontact of the electrical switch 74. The microcomputer 50 of theelectronic lock receives the contact-closure signal (i.e., detectingthat the electrical switch is closed) and treats the signal asindication that the vending machine is to be accessed using a mechanicalkey. In response, the microcomputer set its operation mode such that inthe future it will unlock the door of the vending machine in response todetecting the closure of the contact of the electrical switch 74. Thus,from this point forward, the vending machine is accessed using themechanical key 78, which replaces one or more types of electronic keys.

[0044] It will be appreciated that the key learning process describedabove does not require changing or replacing any physical components ofthe lock. If the electronic key for operating the lock on the vendingmachine is stolen or lost, the service person will first use a back-upkey that has the key code of the key that is lost, or a key that has adifferent key code that has been previously learned into the lock, toopen the door. The service person then uses the key learning processdescribed above to change the key code in the memory of the lock to anew value. This field-programmability of the electronic lock makes keymanagement significantly easier and cost-effective, and provides agreater level of key security compared to mechanical keys. In contrast,with conventional vending machines using mechanical locks, themechanical keys may be copied or stolen easily, and the entire lock coreof each of the vending machines affected has to be replaced in order tochange to a different key.

[0045] In the illustrated embodiment, one digit in each key code storedin the lock indicates the type of the key, and there may be up to tendifferent key types. A lock is able to learn one key code for eachallowed key type. A key code of a first type may be that learned from a“primary” electronic key for the vending machine, while a key code of asecond type may correspond to a different electronic key, such as a“master” key that can be used as a back-up in case the primary key islost, stolen, broken, or otherwise unavailable.

[0046] In a preferred embodiment, as briefly mentioned above, differenttypes of electronic keys (indicated by the different values of the keytype digit) are provided that correspond to different levels of security(and the associated complexity of communication) and audit datacollection function. The three types of electronic keys are economy key,standard key, switch-lock, and auto-tracking key. The operation of eachof these three types of keys is described below.

[0047] Referring to FIG. 6., the economy key employs a simple one-waycommunication process for interacting with a corresponding electroniclock on a vending machine. Since the communication process is simplerand the one-way communication does not require a receiver in the key,the key can be build at a lower cost. As shown in FIG. 6, the memory 102of the economy key contains a key code 104, an encryption code 106, anda random number 108. In a preferred embodiment, the key starts with agiven value of the random number, and the random number changes everytime the key cycles through a key code transmission. When a useractivates the key by pressing the button on the key, the key uses theencryption code to encrypt (step 110) the key code 104 together with therandom number 108, and transmits the encrypted number 112 to theelectronic lock. When the electronic lock receives the transmittedencrypted data, it decrypts (step 116) the data with the encryption code118 in its memory 52. The lock then retrieves the key code 122 from thedecrypted data and compares it with the key code 120 of the same type inits memory. If the two key codes do not match, the process ends. If theymatch, the electronic lock proceeds to unlock the door of the vendingmachine.

[0048] In comparison with the economy key, the standard key provides amore secure unlocking process that requires 2-way encryptedcommunications between the key and the electronic lock. The 2-waycommunications is in the form of a bidirectional challenge-responseprocess. Referring to FIG. 7, the memory 130 of the key contains the keycode 132, the encryption code 134, a real-time clock timestamp 136, anda random number 138. Similarly, the memory 52 of the electronic lock ofthe vending machine contains a learned key code 140, the encryption code142, and an ID 146 of the electronic lock. When the service personpresses the transmission button on the electronic key, the electronickey encrypts (step 150) the key code 132 in its memory together with thetime stamp 136 and the random number 138, and transmits the encryptedkey code and timestamp to the electronic lock of the vending machine.The electronic lock receives the transmitted data 152 through itsinfrared communication interface and decrypts (step 156) the receiveddata with the encryption code 142 in its memory. Next, the electroniclock compares (step 162) the decrypted key code 160 with the key code140 of the same type in its memory. If the two key codes don't match,the process ends, and the door will not be unlocked. In that case, theelectronic lock sends a code to the key to indicate that the key hastried an incorrect key code.

[0049] If the two key codes match, the process continues and enters asecond phase in which the electronic lock transmits data to theelectronic key. Specifically, the lock encrypts (step 164) the key code,the lock ID 146, and the random number. It then transmits the encryptedkey code, lock ID, and the random number (originally sent by the key) tothe electronic key. The electronic key receives the encrypted data 166and decrypts (step 168) the data to retrieve the key code and the lockID. If the key determines (step 172) that the key code 170 returned bythe lock matches the key code 132 in the memory of the key, it storesdata regarding the access event, including the lock ID, in an audittrail data portion of the key's memory for audit purposes.

[0050] The key then proceeds to the third phase of the unlockingprocess, in which the key communicates to the lock to allow access. Tothat end, the key encrypts (step 176) the received lock ID and transmitsthe encrypted lock ID and random number to the lock. The lock receivesthe transmitted data 180 and decrypts (step 182) the data to retrievethe lock ID. If the received lock ID 186 matches the lock ID 146 storedin the memory of the lock, the microcomputer of the lock proceeds tounlock the door of the vending machine.

[0051] The unlocking operation described above has several advantages.It allows the transfer of the lock ID and the key codes between theelectronic key and the lock on the vending machine without repeatingnumbers or a distinguishable pattern of numbers in case of eavesdroppingof repeated access attempts. It also prevents a transfer of data betweenthe key and the lock with different encryption codes. Further, itprovides a consistent and secure means of data transfer between the keyand the lock for a condition where many keys with the same key code willbe expected to communicate with many locks on different vending machinescontaining that key code. This bi-directional challenge-responseencryption scheme provides no risk of the keys and the locks going outof sequence, which is a common problem with unidirectional rolling-codeencryption systems.

[0052] The lock ID code is used in the unlocking operation describedabove for generating audit data for audit trail identification purposesand also for data transfer encryption purposes. In an alternativeembodiment, however, it is also be used to provide a method forcontrolling which vending machines a key is allowed to access. In thismethod, there may be many keys containing the same key code, and theremay be many vending machines that have “learned” the same key code. Itis possible, however, to specify which vending machines a given key isallowed to access so that a single key cannot open all the vendingmachines. Referring to FIG. 8, this is accomplished by loading a list oflock ID codes 192 into the memory 130 of that key prior to operation.During an unlocking operation, the key receives a lock ID 174 from theelectronic lock on the vending machine and compares the received lock IDwith the list of lock IDs 192 in its memory. Only if it is determined(step 198) that the received lock ID 174 matches one of the lock IDs inthe list will the key proceed to send the unlock command signal (e.g.,the transmission 180 in the third phase) to the electronic lock. Asshown in FIG. 8, the unlocking process is otherwise similar to thatshown in FIG. 7. This method of access control provides supervisors ofthe operation the flexibility of allowing or disallowing a given key toaccess selected vending machines.

[0053] In an alternative embodiment, an electronic key may also beprogrammed with other types of limits of operation of the key. Forinstance, the key may be programmed with limit registers that containvalues chosen by a supervisor to limit the operation of that particularkey. In a preferred embodiment, the limit registers 200 (FIG. 4) arepart of the non-volatile memory 52. The operation limits include, forexample, time of data, date, number of days, number of accesses, numberof accesses per day, etc. When the user of the key presses the button onthe key to initiate a key code transmission, the microcomputer of thekey first compares the limits set in the registers with a real-timeclock in the key and an access counter in the key memory. If any of thelimits is exceeded, the key will not transmit the key code to theelectronic lock and will terminate the operation.

[0054] Referring to FIG. 9, the key operation limits may be set by thesupervisor 208 of the employee that uses the electronic key 212 toaccess vending machines in the field. The limits can be selected byusing a personal computer (PC) 210 with the appropriate softwareprogram. The limits for each key may be customized depending on, forinstance, the work schedule or habits of the employee to whom the key isgiven. For illustration purposes, FIG. 9 shows an exemplary userinterface screen 216 for prompting the user 208 to enter the limits.After the limits are selected on the PC 210, they are loaded from the PCinto the operation limit registers in the electronic key 212 in acommunication process between a key read/write device 218 and the key.During this communication process, other types of data, such as data forupdating the real-time clock in the key, may also be loaded into thekey. Also, the communication process may be used to transfer data, suchas the audit trail data collected from vending machines by the keyduring previous field operations, from the electronic key 212 to the PC210.

[0055] In accordance with an aspect and alternative embodiment of theinvention, an advantage of electronic keys is that they can be used torecord and collect and track the attempted accesses of locks on vendingmachines in the field. Keys that provide this function are of the“auto-tracking” type mentioned above. Referring to FIG. 10, with anauto-tracking key 212, each access attempt triggers an audit data eventin both the electronic key and the electronic lock in the vendingmachine 20. To that end, a space for audit data is reserved in each ofthe nonvolatile memories of the key 212 and the lock 48. During anaccess attempt, the key 212 transfers the key code 220 and a timestamp222 to the lock. Regardless of whether the access attempt succeeds orfails, the lock stores the key code and timestamp in its audit datamemory. In one implementation, the lock will filter the number ofaccesses from a given key in a given period (e.g., one attempt per keyfor every 20 minutes) so that it does not create a separate record foreach access attempt. It may, however, include data in the recordcounting the number of access attempts from the key in the time period.This minimizes the chances that when a key is used to make many accessattempts in a row it will fill the audit trail memory and erase existingrecords of previous access attempts. One way to set this time period inthe lock is to transfer the value of the period from a key (which is inturn set by a supervisor using a PC) to the lock.

[0056] If the access attempt results in a key code mismatch or if thekey is disallowed for access because an operation limit in its limitregisters is reached, the access process is terminates. In either case,the lock transfers its lock ID 228 to the key 212. The key is expectedto store the lock ID and the timestamp in its audit data memory as aninvalid access attempt.

[0057] If, on the other hand, the access attempt results in a validmatch of key code and the key has not exceeded its operation limits, thelock still transfers its lock ID to the key 212. The key 212 then storesthe lock ID and timestamp in the audit data memory as a record of aproper access. In addition, as the electronic key is an auto-trackingkey, the lock transfers all the audit data 228 entries in its audit datamemory to the key. The data in the audit data memory includes the lockID, a record for each access attempt that includes the entire key code(including the key ID digits) received from the key that made the accessattempt, and the timestamp for that access attempt. The auto-trackingkey 212 then stores the audit data 228 of the lock in its ownnonvolatile memory. In this regard, each key preferably is capable ofuploading the audit data memories of 200-300 vending machines. Thiseliminates the need for a separate process or equipment in the field forperforming the same data retrieving function.

[0058] When the electronic keys 212 are returned to the home base, theaudit data they generated themselves and the audit data they collectedfrom the vending machines 20 can be transferred to a central controlcomputer 210. The audit data can be downloaded to the PC 210 by thesupervisor using the key read/write device 218 that is also used forprogramming the electronic key.

[0059] By way of example, FIG. 11 shows exemplary audit data collectedby an auto-tracking key from a vending machine. In this example, the keycode stored in the lock on the vending machine is “A100”. The vendingmachine was accessed using the auto-tracking key on Dec. 8, 2001. Sincethe key contains the correct key code, the access operation issuccessful. Thereafter, there were two unauthorized access attempts. Thefirst unauthorized access attempt on Dec. 19, 2001 failed, because thekey code (“A500”) in the electronic key did not match the key code inthe lock. The second unauthorized attempt on December 20 used a stolenkey with the right key code and was successful. When the auto-trackingkey is used on Dec. 22, 2001 to unlock the vending machine, the auditdata 232 stored in the memory of the electronic lock on that vendingmachine are transferred to the auto-tracking key, which stores thetransferred audit data in its own memory. As stored in the key, theaudit data 236 identifies the vending machine from which the audit dataare uploaded. The audit data 236 stored in the key are later downloadingto the home base PC.

[0060] Due to the various complexities of this system concerningmultiple key users, key codes, and the multiple keys sharing the samekey codes, as well as the flexibility provided by the ease of changingaccess codes of the vending machines in the field, it is often desirableto provide simple diagnostic capabilities to the keys, electronic locks.It may also be desirable to provide special reader tools for use in thefield.

[0061] In one implementation, the electronic key uses its LED light toprovides several diagnostic signals to the user when its START button ispressed and when it is communicating with the electronic lock. If thekey correctly communicates with the lock and the key codes match, theLED light is on continuously for about five seconds. If the keycorrectly communicates with the lock but the key codes do not match, theLED light flashes around five times a second for about five seconds. Ifthe key cannot establish correct communication with the lock, the LEDlight is set to flash faster, such as 25 times a second, for about fiveseconds. If the key correctly communicates with the lock and the keycodes match, but the operation limits set in the limit registers areexceeded, the LED flashes at a lower frequency, such as three times persecond for about 3 seconds. If the START switch of the key is pressedand the key does not communicate with the lock and its operation limitsare exceeded, the LED first flash quickly, such as 25 times per second,for up to 5 seconds, and then flash three time per second for up tothree seconds.

[0062] In a preferred embodiment, a diagnostic tool 240 is used in thefield to communicate with electronic locks on vending machines, whichprovide diagnostic information in the event of problems with theoperation of the lock or the door. As shown in FIG. 10, the diagnostictool 240 includes a display 242 that displays information read from theelectronic lock. For instance, the display may show each of the accesscontrol key codes stored in the non-volatile memory of the lock, thelock ID of that lock, and any other information pertaining to the stateof the electronic lock, such as an indication of whether the lockexpects the door to be in a locked or unlocked state based on aposition-control feedback measured by the lock circuit.

[0063] In a preferred embodiment, security measures are implemented inthe electronic key concerning key tampering by replacing the battery inthe key. It is possible that the employees or thieves that gain accessto the electronic keys will attempt to trick the security of the systemby tampering with the key. Since the key contains the clock thatprovides the time and date of access limiting, it is likely the userswill attempt to disable or trick the clock to override the accesslimits. For example, if the key operation limits are set to only allowaccesses between 7 AM and 6 PM, the user may attempt to disconnect thebattery of the key in-between lock accesses to stop the clock in the keyfrom counting down the time and disabling the key.

[0064] Referring to FIG. 13, to reduce of risk of clock tampering byremoving the battery, the key is programmed such that it will reset itsclock back to approximately the correct time and date after the batteryis reconnected. This feature is provided for both cases of the batterygoing low naturally or if it is tampered with by the user. To that end,each time the START button 36 of the key is pressed (step 290), themicrocomputer 80 of the key reads the time and date from the clock 94(step 292), and stores the time and date data 298 in the non-volatilememory 82 of the key (step 296). Alternatively, the key may store thetime and date periodically, such as every 1-2 minutes. Referring now toFIG. 14, if the key battery is disconnected and later a battery isinserted into the key, the key starts a power-up process (step 300). Themicroprocessor is programmed to read the back-up time and date 298stored in the non-volatile memory 82 (step 302) and writes that time anddate into the clock 94 (step 306). The clock will then run based on therestored time and date as a substitute until the electronic key isre-docked into the cradle and the home base computer 210 stores a newaccurate time and date in the clock of the key. When the restored timeand date is in use, the key can still be used to access locks on thevending machines as long as the operation limits of the key are notexceeded.

[0065] In addition to the time-restoration feature, the microcomputer 80in the key employs logic that counts the number of times the battery isremoved and will immediately disable the key indefinitely if the batteryis disconnected and re-connected more than a pre-selected number oftimes, such as three times. Specifically, the microprocessor maintainsin the non-volatile memory 82 a counter 312 that counts the number oftimes the key has been powered up since the last docking of the key.This counter 312 is cleared each time the key is docked. Each time abattery is inserted in the key and the microcomputer 80 goes through thepower-up process (step 306), the microcomputer 80 reads the counter 302(step 316). If the microcomputer determines (step 318) that the counterreading has reached the allowed number of power-up, such as 3 times, itdisables the key from any access operation. If the allowed number ofpower-up is not reached, the microcomputer increments the counter (step320). Thereafter, the key continues with regular key operation, but witheach access attempt the key will store a “battery removed” bit with theaudit data for that access event in the memories of the lock and thekey. This “battery removed” bit indicates that the time and date stampof the access event is recorded after the key battery was disconnected,and that the accuracy of the time and date is questionable.

[0066] Referring to FIG. 15, in accordance with-a feature of analternative embodiment, the vending machine 20 is equipped with anelectronic device for communicating with the home base. Thecommunication device 360 preferably communicates wirelessly, such asover a RF channel, to the computer 210 at the home base of the owner ofthe vending machine. The vending machine also includes a vendorcontroller electronic circuit 362 for controlling the operation of thelock 48. The vendor controller 362 is connected to the lock 48 and thecommunication device 360. The electronic lock 48 working together withthe vendor controller 362 and the communication electronic device 360 incommunication with the home base can accomplish many of the same accesscontrol and auditing functions described above and additionally someinventory and money settlement processes. For example, the communicationdevice 360 can receive a command from the home base to disable operationof the lock 360 regardless if an electronic key with the correct keycode attempts to access the vending machine. Also for example, the lock48 can indicate to home base computer 210 through the communicationdevice 360 which keys have attempted to access of the vending machine.This arrangement eliminates the need to use an electronic key tocollect, store, and transfer the audit events to the home base via thememory and communication medium of the key.

[0067] Moreover, the communication device 360 may be used with thevendor control 362 to keep track of the inventory and the cashtransactions of the machine. In many cases, when the service person(route driver) visits the machine, his job is to fill the machine andcollect money. During this task, the vendor control 362 is involved ininterfacing with the service person to ensure the proper resetting andsettlement processes take place, and that the service person closes thedoor of the vending machine. The vendor controller 362 can inform thehome base computer of the open/close state of the vending machine door.In the case the Route Driver does not satisfy the conditions of thevendor controller 362 by way of inventory or monetary or debit cardprocessing, the vendor controller can send a disable signal to theelectronic lock 48 so the door of the vending machine cannot be closedand locked. Thus, since the service person cannot leave a vendorunlocked, this process would force him to complete the requiredresetting and settlement processes so the vendor controller can allowthe vendor door to be locked before the service person leaves thevending machine.

[0068] Referring now to FIG. 16, in accordance with a feature of apreferred embodiment, the wireless transceiver of the electronic key 26is designed to have limited transmission range and angle to prevent avending machine 380 from being accidentally opened due to receivingstray transmission from the key when the key is used to open anothervending machine 20 in its vicinity. Specifically, the transmitter 382 ofthe key 20 has a pre-defined transmission angle 386. Also, due to thelimited transmission power of the transmitter 382, the transmission fromthe key 26 has a limited transmission power range 388, beyond which thesignal strength is generally too weak for the transceiver 390 of theelectronic lock of the vending machine 20 to reliably detect. In apreferred implementation, the transmission power and the transmissionangle 386 of the key 26 is selected such that the width 392 of thetransmission pattern at the effective transmission range 388 is aboutthe same or smaller than the width of the vending machine 20. Asmentioned above, in a preferred implementation, the transceivers in thekeys and the electronic locks on vending machines are infraredtransmitters for transmitting and receiving infrared signals.

[0069] In view of the many possible embodiments to which the principlesof this invention may be applied, it should be recognized that theembodiments described herein with respect to the drawing figures aremeant to be illustrative only and should not be taken as limiting thescope of the invention. Therefore, the invention as described hereincontemplates all such embodiments as may come within the scope of thefollowing claims and equivalents thereof.

What is claimed is:
 1. A vending machine comprising: a door openable toaccess contents of the vending machine; an electronic lock for lockingand unlocking the door of the vending machine, the electronic lockcomprising a control circuit including a microcomputer, a non-volatilememory, a wireless communication interface for receiving wirelesscommunications, and a learning mode activation device, the microcomputerbeing programmed to receive a learning mode activation signal from thelearning mode activation device and, in response to the learning modeactivation signal, receiving a first key code via the wirelesscommunication interface, and storing the first key code in thenon-volatile memory.
 2. A vending machine as in claim 1, wherein thewireless communication interface receives communications over aninfrared band.
 3. A vending machine as in claim 2, wherein the wirelesscommunication interface includes an infrared receiver disposed behind anitem selection button on the vending machine.
 4. A vending machine as inclaim 3, wherein the infrared receiver is also an infrared transmitter.5. A vending machine as in claim 1, wherein the first key code isreceived by the communication interface in a form of encrypted data, andthe microcomputer is programmed to decrypted the received encrypted datausing an encryption code stored in the non-volatile memory of theelectronic lock.
 6. A vending machine as in claim 1, wherein thecommunication interface is also for transmitting wirelesscommunications, and wherein the microcomputer of the electronic lock isprogrammed to carry out a bi-directional challenge-response processusing encrypted communications with an electronic key to receive asecond key code from the electronic key and unlocking the door of thevending machine when the second key code matches the first key codestored in the non-volatile memory.
 7. A vending machine as in claim 1,wherein the microcomputer of the electronic lock is further programmedto transmit access event data regarding access attempts directed to theelectronic lock to the electronic key after a match is found between thefirst and second key codes.
 8. A vending machine as in claim 1, whereinthe vending machine further includes an electrical switch operable by amechanical lock operable by an associated mechanical key, wherein themicrocomputer of the electronic lock is further programmed to receive atrigger signal from the electrical switch when the microcomputer is setin a learning mode using the learning mode activation device and, inresponse to the trigger signal, enter an operation mode in which themicrocomputer unlocks the door of the vending machine upon receiving asubsequent trigger signal generated by the electrical switch.
 9. Avending machine as in claim 1, further including a communication deviceexternal to the electronic lock for wirelessly communicating with acontrol computer at a remote location, and a lock controller forcontrolling operation of the electronic lock in response to controlcommands received from the control computer via the communicationdevice.
 10. A vending machine as in claim 9, wherein the lock controllerforwards data received from the electronic lock to the communicationdevice for transmission to the control computer.
 11. A vending machineas in claim 8, wherein the data received from the electronic lockinclude access event data regarding access attempts directed to theelectronic lock of the vending machine.
 12. A vending machine as inclaim 1, further including a state indication device operable by themicrocomputer to indicate operation status of the electronic lock.
 13. Avending machine as in claim 1, wherein the microcomputer of theelectronic lock is programmed to receive an encrypted transmissionthrough the wireless communication interface, decrypt the receivedencrypted transmission to retrieve a second key code, compare the secondkey code with the first key code stored in the non-volatile memory, andunlock the door of the vending machine when the second key code matchesthe first key code.
 14. A vending machine comprising: a door openablefor accessing contents of the vending machine; and an electronic lockfor locking the door of the vending machine, the electronic lockcomprising an electronic control circuit including a microprocessor, anon-volatile memory, and a wireless communication interface fortransmitting and receiving wireless communications, the microcomputerbeing programmed to perform a bi-directional challenge-response processwith an electronic key using encrypted communications through thewireless communication interface, wherein during the challenge-responseprocess the microcomputer receives a key code transmitted from theelectronic key, compares the received key code with a key code stored inthe non-volatile memory of the electronic lock, and unlocks the door ofthe vending machine if the received key code matches the key code storedin the non-volatile memory.
 15. A vending machine as in claim 14,wherein the wireless communication interface includes an infraredtransceiver for transmitting and receiving infrared signals.
 16. Avending machine as in claim 14, wherein the infrared transceiver isdisposed behind an item selection button on the vending machine.
 17. Avending machine as in claim 14, wherein the non-volatile memory has anencryption code stored therein for use by the microcomputer in dataencryption and decryption during the bi-directional challenge-responseprocess.
 18. A vending machine as in claim 14, wherein the non-volatilememory has multiple key codes stored therein.
 19. A vending machine asin claim 14, wherein the microcomputer of the electronic lock is furtherprogrammed to transmit access event data regarding access attemptsdirected to the electronic lock to the electronic key if the receivedkey code matches the key code stored in the non-volatile memory.
 20. Avending machine as in claim 14, further including a communication deviceexternal to the electronic lock for wirelessly communicating with acontrol computer at a remote location, and a lock controller forcontrolling operation of the electronic lock in response to controlcommands received from the control computer via the communicationdevice.
 21. A vending machine as in claim 20, wherein the lockcontroller forwards data received from the electronic lock to thecommunication device for transmission to the control computer.
 22. Avending machine as in claim 21, wherein the data received from theelectronic lock include access event data regarding access attemptsdirected to the electronic lock of the vending machine.
 23. A vendingmachine as in claim 14, further including a state indication deviceoperable by the microcomputer to indicate operation status of theelectronic lock.
 24. An electronic key comprising: a clock; amicrocomputer; an infrared communication interface for transmitting andreceiving communications over an infrared band; a non-volatile memoryhaving stored therein a key code, a power-up counter, and a clock databack-up buffer; and an activation device connected to the microcomputerand operable for generating an activation signal for triggering themicrocomputer to initiate a key code transmission operation in which theinfrared communication interface is used to transmit the key code storedin the non-volatile memory, wherein the microcomputer is programmed toperform a bi-directional challenge-response process during a keytransmission operation with an electronic lock on a vending machineusing encrypted communications through the infrared communicationinterface.
 25. An electronic key as in claim 24, wherein themicrocomputer is further programmed to increment the power-up countereach time the electronic key is powered up by insertion of a battery,determine whether the power-up counter has reached a pre-selectednumber, and select not to initiate a key code transmission operation inresponse to an activation signal from the activation device if thepower-up counter has reached the pre-selected number.
 26. An electronickey as in claim 24, wherein the microcomputer is further programmed toread clock data from the clock in response to receiving an activationsignal from the activation device, and store the clock data into theclock data backup buffer in the non-volatile memory, and to reset theclock using the clock data stored in the clock data backup buffer whenthe electronic key is powered up by insertion of a battery.
 27. Anelectronic key as in claim 24, wherein the microcomputer is furtherprogrammed to store an access event record in the non-volatile memorywhen the key code is transmitted in response to receiving an activationsignal from the activation device, and wherein the access event recordincludes a flag that is set when the power-up counter is non-zero. 28.An electronic key as in claim 24, wherein the non-volatile memoryfurther includes at least one operation limit register for storing anoperation limit of the electronic lock, and wherein the microcomputer isprogrammed to terminate a key code transmission operation if theoperation limit is reached.
 29. An electronic key as in claim 24,wherein the non-volatile memory further has an encryption code storedtherein, and the microcomputer is programmed to use the encryption codeto encrypt communications for transmitting the key code in thebidirectional challenge-response process.
 30. An electronic key as inclaim 24, wherein the microcomputer is further programmed to receiveaudit data from an electronic clock on a vending machine accessible bythe electronic key and storing the received audit data in thenon-volatile memory of the electronic lock.
 31. An electronic key as inclaim 24, wherein the activation device is a button switch.
 32. Anelectronic key as in claim 24, wherein the non-volatile memory furtherhas a key identification number of the electronic key stored therein.33. An electronic key as in claim 24, wherein the microcomputer isfurther programmed to continuously use the infrared communicationinterface to transmit the key code for a preselected period of time inresponse to each activation signal from the activation device.
 34. Anelectronic key as in claim 24, wherein the infrared communicationinterface includes an infrared transceiver having a transmission patternwith a transmission angle and a transmission power range set such thatan effective width of the transmission pattern at the transmission powerrange is substantially identical or less than a width of the vendingmachine.
 35. A combination of a vending machine with an electronic lockmounted therein and an electronic key for accessing the electronic lock,the electronic key having a wireless transmitter and being programmed touse the wireless transmitter to transmit a key code to the electroniclock on the vending machine, the wireless transmitter having atransmission pattern with a transmission angle and a transmission powerrange set such that an effective width of the transmission pattern atthe transmission power range is substantially identical or less than awidth of the vending machine.
 36. A combination as in claim 35, whereinthe transmitter is an infrared transmitter.
 37. A combination as inclaim 36, wherein the transmitter is also an infrared receiver.
 38. Acombination as in claim 36, wherein the vending machine has at least oneitem selection button, and the electronic lock has an infrared receiverdisposed behind the item selection button for receiving infraredtransmission from the transmitter of the electronic key.
 39. Acombination as in claim 38, wherein the infrared receiver of theelectronic lock and the infrared transmitter of the electronic key areboth transceivers, and wherein the electronic lock and electronic keyare programmed to perform a bi-directional challenge-response process inwhich the key code of the electronic key is transmitted to theelectronic lock.
 40. An electronic security system for vending machines,comprising: a home base computer; an electronic lock accessible using anassociated electronic key, a communication device for communication withthe home base computer, and a lock controller in each of the vendingmachines, the electronic lock controlling access to a door of said eachvending machine, the lock controller being connected to the electroniclock for controlling operation of the electronic lock in response tocommands received from the home base computer through the communicationdevice.
 41. An electronic security system as in claim 40, wherein thecommunication device in said each vending machine communicateswirelessly with the home base computer.
 42. An electronic securitysystem as in claim 40, wherein the communication device in said eachvending machine communicates wirelessly with the home base computer overa RF band.
 43. An electronic security system as in claim 40, wherein theelectronic lock in said each vending machine is further programmed toperform, during the key transmission operation, a bidirectionalchallenge-response process with the associated electronic key usingencrypted communications, the challenge-response process includingreceiving a key code from the electronic key and comparing the receivedkey code with a key code stored in the electronic lock.
 44. Anelectronic security system as in claim 43, wherein the electronic lockin said each vending machine is further programmed to send dataconcerning access attempts directed to the electronic lock through thecommunication device to the home base computer.